1. Field of the Invention
This invention generally relates to a biaxially rotational structure, and more particularly to a biaxially rotational structure for a planar antenna in which the angle of the planar antenna can be adjusted biaxially.
2. Description of the Related Art
Conventional antenna for one-dimension polarized wireless communication is configured as a retractable elongated rod. For receiving the one-dimension polarized wireless communication signals, the conventional retractable elongated antenna can be adjusted its orientation at its joint according to the polarized direction of the one-dimension polarized wireless communication signals. However, due to the obstruction of any barriers and the interference of any other signals or electromagnetic fields, the one-dimension polarized wireless communication signal will significantly decay in the transmission path. Even though the antenna is adjusted to its optimal position, the one-dimension polarized wireless communication signal received by the antenna is still not clear enough as required.
In order to overcome the disadvantages of the one-dimension polarized wireless communication, a planar antenna for two-dimension polarized wireless communication is developed. With the radio frequency (RF) signal, the distances that the planar antenna can cover are much greater. For use in the two-dimension polarized wireless communication, the planar antenna has two freedoms of rotation such that the inclined angle and the directional angle of the planar antenna can be adjusted to conform to the polarized angle of the two-dimension polarized wireless communication signal. Accordingly, the planar antenna can receive better wireless communication signal.
FIG. 1 depicts a conventional planar antenna which mainly comprises an antenna 1, a box set 2, a hollow tube body 31, ear members 32, a plate 41, two supports 42, screws 43 and a cable. The supports 42 of the plate 41 press against the ear members 32 of the hollow tube body 31 such that the frictional force between the supports 42 and the ear members 32 enables the hollow tube body 31 to rotate horizontally with respect to the box set 2. The antenna 1 also can rotate with respect to vertical direction of the box set 2. According to the conventional planar antenna, the user might rotate the planar antenna along the vertical direction without any limitation and the cable therein might be tangled or even be broken. Besides, the conventional planar antenna utilizes friction force to sustain the twist force of the cable and the gravity force of the planar antenna. When the conventional planar antenna has been used for a long while, the frictional parts of the conventional planar antenna will wear out and thus will not function well any longer.